A wifi jammer, the fault is that it does not work for CDMA phones, I read the manual, the machine should be able to interfere with four frequency bands.
CDMA: 869-894MHz
Cell phone: 935-960MHz
Cell phone: 1805-1880MHz
SmarTone: 1900-1990MHz
The wifi signal jammer works, the circuit structure is understood. For electronics enthusiasts, after understanding the working principle can simply do whatever you want, immediately design and hands-on production to try, it works very well, I wrote this article will be my design and production process to tell interested friends.
How wifi jammer works?
The working principle is to use the sawtooth wave control voltage controlled oscillator, so that it generates the sweep signal of the working band, each sweep cycle, which is equal to adding a wide pulse (due to the positive range of the sawtooth wave) and a narrow pulse (due to the inverse range of the sawtooth wave) at each frequency point in the working band, which destroys the data exchange between the cell phone and the base station in the coverage area, the cell phone can not get the data of the base station, can only show no signal, of course, it can not communicate. The cell phone can not get the data from the base station, so it can only show no signal, and of course, no communication.
According to the analysis, the sawtooth wave here is not used for measurement, just to allow the voltage controlled oscillator to work, do not what the accuracy, the use of the simpler circuit shown in the figure below to generate.
The circuit is simple, the components are easy to obtain, the accuracy is not high, but can fully meet the requirements. Here, the accuracy of the lower return range of the longer sawtooth wave may also be better? Voltage controlled oscillator and RF amplification operating frequency are relatively high.
After experimentation, the four frequency bands used in cell phone communications can be installed on this board, the two high frequency bands with the second harmonic. Of course, you can also be close to each other two frequency bands combined with a circuit board, but the output will be much smaller. Using a circuit board to cover four bands can also be achieved, but the output is smaller, because the RF energy will be more spread out.
